mpegtsenc.c

Trolltech公司发布的图形界面操作系统。可在qt-embedded-2.3.10平台上编译为嵌入式图形界面操作系统。

    MpegTSService *service;
    uint8_t data[1012], *q, *desc_list_len_ptr, *desc_len_ptr;
    int i, running_status, free_ca_mode, val;
    
    q = data;
    put16(&q, ts->onid);
    *q++ = 0xff;
    for(i = 0; i < ts->nb_services; i++) {
        service = ts->services[i];
        put16(&q, service->sid);
        *q++ = 0xfc | 0x00; /* currently no EIT info */
        desc_list_len_ptr = q;
        q += 2;
        running_status = 4; /* running */
        free_ca_mode = 0;

        /* write only one descriptor for the service name and provider */
        *q++ = 0x48;
        desc_len_ptr = q;
        q++;
        *q++ = 0x01; /* digital television service */
        putstr8(&q, service->provider_name);
        putstr8(&q, service->name);
        desc_len_ptr[0] = q - desc_len_ptr - 1;

        /* fill descriptor length */
        val = (running_status << 13) | (free_ca_mode << 12) | 
            (q - desc_list_len_ptr - 2);
        desc_list_len_ptr[0] = val >> 8;
        desc_list_len_ptr[1] = val;
    }
    mpegts_write_section1(&ts->sdt, SDT_TID, ts->tsid, 0, 0, 0,
                          data, q - data);
}

static MpegTSService *mpegts_add_service(MpegTSWrite *ts, 
                                         int sid, 
                                         const char *provider_name, 
                                         const char *name)
{
    MpegTSService *service;

    service = av_mallocz(sizeof(MpegTSService));
    if (!service)
        return NULL;
    service->pmt.pid = DEFAULT_PMT_START_PID + ts->nb_services - 1;
    service->sid = sid;
    service->provider_name = av_strdup(provider_name);
    service->name = av_strdup(name);
    service->pcr_pid = 0x1fff;
    dynarray_add(&ts->services, &ts->nb_services, service);
    return service;
}

static void section_write_packet(MpegTSSection *s, const uint8_t *packet)
{
    AVFormatContext *ctx = s->opaque;
    put_buffer(&ctx->pb, packet, TS_PACKET_SIZE);
}

static int mpegts_write_header(AVFormatContext *s)
{
    MpegTSWrite *ts = s->priv_data;
    MpegTSWriteStream *ts_st;
    MpegTSService *service;
    AVStream *st;
    int i, total_bit_rate;

    ts->tsid = DEFAULT_TSID;
    ts->onid = DEFAULT_ONID;
    /* allocate a single DVB service */
    service = mpegts_add_service(ts, DEFAULT_SID, 
                                 DEFAULT_PROVIDER_NAME, DEFAULT_SERVICE_NAME);
    service->pmt.write_packet = section_write_packet;
    service->pmt.opaque = s;

    ts->pat.pid = PAT_PID;
    ts->pat.cc = 0;
    ts->pat.write_packet = section_write_packet;
    ts->pat.opaque = s;

    ts->sdt.pid = SDT_PID;
    ts->sdt.cc = 0;
    ts->sdt.write_packet = section_write_packet;
    ts->sdt.opaque = s;

    /* assign pids to each stream */
    total_bit_rate = 0;
    for(i = 0;i < s->nb_streams; i++) {
        st = s->streams[i];
        ts_st = av_mallocz(sizeof(MpegTSWriteStream));
        if (!ts_st)
            goto fail;
        st->priv_data = ts_st;
        ts_st->pid = DEFAULT_START_PID + i;
        ts_st->payload_pts = AV_NOPTS_VALUE;
        /* update PCR pid if needed */
        if (st->codec.codec_type == CODEC_TYPE_VIDEO && 
            service->pcr_pid == 0x1fff)
            service->pcr_pid = ts_st->pid;
        total_bit_rate += st->codec.bit_rate;
    }
    if (total_bit_rate <= 8 * 1024)
        total_bit_rate = 8 * 1024;
    ts->sdt_packet_freq = (total_bit_rate * SDT_RETRANS_TIME) / 
        (TS_PACKET_SIZE * 8 * 1000);
    ts->pat_packet_freq = (total_bit_rate * PAT_RETRANS_TIME) / 
        (TS_PACKET_SIZE * 8 * 1000);
#if 0
    printf("%d %d %d\n", 
           total_bit_rate, ts->sdt_packet_freq, ts->pat_packet_freq);
#endif

    /* write info at the start of the file, so that it will be fast to
       find them */
    mpegts_write_sdt(s);
    mpegts_write_pat(s);
    for(i = 0; i < ts->nb_services; i++) {
        mpegts_write_pmt(s, ts->services[i]);
    }
    put_flush_packet(&s->pb);

    return 0;

 fail:
    for(i = 0;i < s->nb_streams; i++) {
        st = s->streams[i];
        av_free(st->priv_data);
    }
    return -1;
}

/* send SDT, PAT and PMT tables regulary */
static void retransmit_si_info(AVFormatContext *s)
{
    MpegTSWrite *ts = s->priv_data;
    int i;

    if (++ts->sdt_packet_count == ts->sdt_packet_freq) {
        ts->sdt_packet_count = 0;
        mpegts_write_sdt(s);
    }
    if (++ts->pat_packet_count == ts->pat_packet_freq) {
        ts->pat_packet_count = 0;
        mpegts_write_pat(s);
        for(i = 0; i < ts->nb_services; i++) {
            mpegts_write_pmt(s, ts->services[i]);
        }
    }
}

/* NOTE: pes_data contains all the PES packet */
static void mpegts_write_pes(AVFormatContext *s, AVStream *st,
                             const uint8_t *payload, int payload_size,
                             int64_t pts)
{
    MpegTSWriteStream *ts_st = st->priv_data;
    uint8_t buf[TS_PACKET_SIZE];
    uint8_t *q;
    int val, is_start, len, ts_len, header_len;

    is_start = 1;
    while (payload_size > 0) {
        retransmit_si_info(s);

        /* prepare packet header */
        q = buf;
        *q++ = 0x47;
        val = (ts_st->pid >> 8);
        if (is_start)
            val |= 0x40;
        *q++ = val;
        *q++ = ts_st->pid;
        *q++ = 0x10 | ts_st->cc;
        ts_st->cc = (ts_st->cc + 1) & 0xf;
        if (is_start) {
            /* write PES header */
            *q++ = 0x00;
            *q++ = 0x00;
            *q++ = 0x01;
            if (st->codec.codec_type == CODEC_TYPE_VIDEO)
                *q++ = 0xe0;
            else
                *q++ = 0xc0;
            if (pts != AV_NOPTS_VALUE)
                header_len = 8;
            else
                header_len = 3;
            len = payload_size + header_len;
            *q++ = len >> 8;
            *q++ = len;
            *q++ = 0x80;
            if (pts != AV_NOPTS_VALUE) {
                *q++ = 0x80; /* PTS only */
                *q++ = 0x05; /* header len */
                val = (0x02 << 4) | 
                    (((pts >> 30) & 0x07) << 1) | 1;
                *q++ = val;
                val = (((pts >> 15) & 0x7fff) << 1) | 1;
                *q++ = val >> 8;
                *q++ = val;
                val = (((pts) & 0x7fff) << 1) | 1;
                *q++ = val >> 8;
                *q++ = val;
            } else {
                *q++ = 0x00;
                *q++ = 0x00;
            }
            is_start = 0;
        }
        /* write header */
        ts_len = q - buf;
        put_buffer(&s->pb, buf, ts_len);
        /* write data */
        len = TS_PACKET_SIZE - ts_len;
        if (len > payload_size)
            len = payload_size;
        put_buffer(&s->pb, payload, len);
        payload += len;
        payload_size -= len;
        ts_len += len;
        /* stuffing */
        len = TS_PACKET_SIZE - ts_len;
        if (len > 0) {
            memset(buf, 0xff, len);
            put_buffer(&s->pb, buf, len);
        }
    }
    put_flush_packet(&s->pb);
}

static int mpegts_write_packet(AVFormatContext *s, int stream_index,
                               const uint8_t *buf, int size, int64_t pts1)
{
    AVStream *st = s->streams[stream_index];
    MpegTSWriteStream *ts_st = st->priv_data;
    int len;

    while (size > 0) {
        len = DEFAULT_PES_PAYLOAD_SIZE - ts_st->payload_index;
        if (len > size)
            len = size;
        memcpy(ts_st->payload + ts_st->payload_index, buf, len);
        buf += len;
        size -= len;
        ts_st->payload_index += len;
        if (ts_st->payload_pts == AV_NOPTS_VALUE)
            ts_st->payload_pts = pts1;
        if (ts_st->payload_index >= DEFAULT_PES_PAYLOAD_SIZE) {
            mpegts_write_pes(s, st, ts_st->payload, ts_st->payload_index,
                             ts_st->payload_pts);
            ts_st->payload_pts = AV_NOPTS_VALUE;
            ts_st->payload_index = 0;
        }
    }
    return 0;
}

static int mpegts_write_end(AVFormatContext *s)
{
    MpegTSWrite *ts = s->priv_data;
    MpegTSWriteStream *ts_st;
    MpegTSService *service;
    AVStream *st;
    int i;

    /* flush current packets */
    for(i = 0; i < s->nb_streams; i++) {
        st = s->streams[i];
        ts_st = st->priv_data;
        if (ts_st->payload_index > 0) {
            mpegts_write_pes(s, st, ts_st->payload, ts_st->payload_index,
                             ts_st->payload_pts);
        }
    }
    put_flush_packet(&s->pb);
        
    for(i = 0; i < ts->nb_services; i++) {
        service = ts->services[i];
        av_freep(&service->provider_name);
        av_freep(&service->name);
        av_free(service);
    }
    av_free(ts->services);

    for(i = 0; i < s->nb_streams; i++) {
        st = s->streams[i];
        av_free(st->priv_data);
    }
    return 0;
}

AVOutputFormat mpegts_mux = {
    "mpegts",
    "MPEG2 transport stream format",
    "video/x-mpegts",
    "ts",
    sizeof(MpegTSWrite),
    CODEC_ID_MP2,
    CODEC_ID_MPEG2VIDEO,
    mpegts_write_header,
    mpegts_write_packet,
    mpegts_write_end,
};
#endif